We present an approach to identify the 3D point of regard and the fixated object in real-time based on 2D gaze videos without the need for manual annotation. The approach does not require additional hardware except for the mobile eye tracker. It is currently applicable for scenarios with static target objects and requires an instrumentation of the environment with markers. The system has already been tested in two different studies. Possible applications are visual world paradigms in complex 3D environments, research on visual attention or human-human/human-agent interaction studies.